Intensifying Escherichia coli inactivation in apple juice using a UV-C-based process

• UV-C inactivated Escherichia coli >5 logs in water and apple juice under optimal settings. • Lamp distance and liquid thickness significantly affected inactivation kinetics. • The Weibull model accurately described E. coli reduction across all treatments. • Apple juice showed lower efficacy due to reduced UV-C transmittance. • UV-C is a sustainable alternative to thermal processing in juice safety. This study evaluated the inactivation kinetics of Escherichia coli in clarified apple juice (CAJ) and distilled water under UV-C light with varying exposure times. A 2-level factorial design assessed the distance from the lamp (1 cm or 5 cm) and the liquid layer thickness (1.8 mm or 3.5 mm). The research explored how changes in UV-C intensity could enhance E. coli inactivation kinetics while decreasing energy use and processing time. The surviving E. coli were counted, and inactivation curves were modeled using the Weibull equation. A reduction of >5 log 10 in the bacterial population was achieved with a minimum thickness, minimal lamp-sample distance, and prolonged exposure. E. coli showed the highest inactivation rate in water, with a notable reduction in CAJ, which was less effective due to lower UV-C transmittance. The Weibull distribution of resistances accurately described the experimental values, exhibiting upward concavity. Factorial design analysis predicts UV-C treatment outcomes across various conditions, suggesting innovations in reactor design to improve disinfection efficiency and energy use. UV-C radiation is a sustainable alternative for enhancing food safety protocols in juice processing compared to traditional heat treatments.